Android aspect ratios: What should designers design to?

The Android ecosystem consists of hundreds of different device types with both phone and tablet versions. This freedom can make it difficult for mobile designers to ensure that their design works as intended on all devices. As it turns out, however, almost all Android devices fall have one of the same few aspect ratios.

Android device screen sizes
Based on a sample size of 682,000 Android devices, OpenSignal compiled a report that included data on device screen size. Below is a graph of that information, where each point represents one device and its location on the graph indicates its screen size for each dimension.

You can see the wide variety of device sizes supported by Android operating systems, ranging from less than 3×2 to larger than 8×6 inches. What is interesting is that the devices seem to group themselves into two categories: those where the width is greater than the height, and vice versa. By separating these two groups and plotting lines of best fit, we get the following:

The slopes of the lines of best fit tell us what the average aspect ratios are. For the vertical oriented devices, this number is approximately 1.6, which would indicate an aspect ratio of 16:10. For the horizontally oriented devices, the number is .66, indicating an aspect ratio of 2:3.

What does this mean for mobile design and development? This data would seem to indicate that designers work with ratios of either 16:10 or 2:3 when designing for multiple Android devices. While many devices do not stick to exactly these ratios, the differences are small enough that hopefully effect on user experience will be minimal.

This blog post was based on data collected by OpenSignal.